The small data transfer feature is an important demand in the technology of machine type communication and intended to lower consumption of network signaling and a bearer resource due to small data transmission. Accordingly, the Third Generation Partnership Project (3GPP) network is desired to be optimized for this feature, and in view of this, the following demands are proposed in the protocol TS22.368.
The small data transfer feature is applicable to a Machine Type Communication (MTC) device sending or receiving a small amount of data. For the small data transfer feature:
First the system shall support small data transmission with minimized influence on the network (e.g., a signaling overhead, a network resource, a reconfiguration delay);
Second the MTC devices with a small amount of data to be sent may be attached to the network or detached from the network; and
Third the definition of a small amount of data may be configured based upon subscription information or a policy of an operator.
The inventors have identified during making of this application the following technical problem in the prior art:
In the prior art, a User Equipment (UE) has to firstly establish a Packet Data Network (PDN) connection prior to transmission of data and then transmit the data over the PDN connection, and it has been a problem to be addressed of how to transmit data when the UE has not established a PDN connection. A procedure of establishing a PDN connection is as illustrated in FIG. 1, and reference can be made to the description of the protocol TS 23.401 for a particular implementation thereof.